Samples of Hydroidomedusa were collected from the Bitung Strait, Indonesia Sea (1. 350 – 1.500 N, 125. 100 – 125. 260 E), during June 2012. Through the analysis of 38 samples, teo new species of Leptomedusae are described, i.e. Eirene pentanemalis Lin, Xu et Huang, sp. nov. and Lovenella polyconcretus Xu, Huang et Guo, sp. nov. All types specimens are deposited in the Third Institute of Oceanography, SOA. The specific diagnoses of two new species are as follows.Eirene pentanemalis Lin, Xu et Huang, sp. nov. (Figs 1-3).The new species has a distinct gastric peduncle; without marginal cirri or lateral cirri; without excretory papillae; 5 radial canals; numerous statocysts. These features place this medusa in the genus Eirene Eschscholtz, 1829.Only 22 valid species of Eirene are known (Bouillon et al., 2006; Guo et al., 2008; Du et al., 2010; Huang et al., 2010). This new species can easily be distinguished from the other species of Eirene by: 1) peduncle short and narrow, without pyramidal base, never extending beyond the velar opening; 2) without excretory papillae, which is close to Eirene brevistylis Huang et Xu, 1994 and E. Brevistyloides Xu, Huang et Du, 2010, but differs from them by: 1) with 5 radial canals, 2) 5 mouth lips and 5 gonads near middle of radial canals; 3) with 10 – 14 marginal tentacles, with 1 rudimentary bulb between the tentacles (exceptionally 2 – 3); 4) with 2 statocysts between the tentacles, each with 2 concretions (Table 1). Etymology. From the Latin pentanemalis, meaning five-radial canals. The species name refers to the number of radial canals.Lovenell polyconcretus Xu, Huang et Guo, sp. nov. (Figs 3, 5)This new species has lateral cirri, no marginal cirri and gastric peduncle; with 16 – 24 statocysts. These features place this medusa in the family Lovenellidae Russell, 1953, genus Lovenella Hincks, 1868.Only 15 valid species of Lovenella are known (Bouillon et al., 2006; Lin et al., 2009, 2010). This new species is closed to Lovenella assimilis (Brown, 1905), L. macrogona Lin, Xu Xian-Zhong, Xu Zhen-Zu et Huang, 2010 and L. sinuosa Lin, Xu, Huang et Wang, 2009, but differs from them by: 1) 4 large oval-shape gonad near umbrellar margin, no split by a median groove; 2) 4 perradial marginal tentacles with black pigmented patch along abxial bulbs, each flanked by 4 – 5 pairs of lateral cirri; 3) 4 interradial marginal warts with black pigmented patch, but without lateral cirri and excretory papillae; 4) with 16 -24 statocyst, each with 5 – 6 concretions (Table 2).Etymology. From the Latin polyconcretus, meaning poly-concretion. The species name refers to each statocyst with poly-concretion. Acta Zootaxonomica Sinica, 38 (4): 756 – 761 (Oct 2013)
