NO. 3586 CYCLOPOID COPEPODS — HUMES AND HO 13 



of leg 1. Endopod of leg 4 with dimensions proportionally much 

 like those in female; first segment 19/x x 17.5ju, second segment 

 24ju X llju, and terminal spine 40.5/z. 



Leg 5 in flat anterior view as shown in figm-e 77, but in undissected 

 specimens appearing in dorsal view as in figm-e 78. Free segment 

 more rectangular than in female, 34ju x lAjd, or 2.43 times longer than 

 wide; terminal setae 51^ and 69^ in length, respectively. 



Leg 6 (fig. 79) a posteroventral flap on genital segment bearing 

 two setae, one SO/i in length and naked, other 45/x with a few lateral 

 hau's. 



Spermatophore not observed. 



Color in life in transmitted light similar to that of female. 



Etymology. — The specific name 2)sammocorae is based on the generic 

 name of the host. 



Method of collection and relation to host. — Like the pre- 

 ceding species, M. ysammocorae was recovered in greatest numbers 

 from the first washings of the coral, without allowing the coral 

 to stand overnight in alcoholized sea v/ater and without crushing. 

 Presumably the copepod lives on the surface of the coral rather than 

 in the polyps. 



Systematic position. — Tlie genus ]\Ionomolgus is at present 

 founded on a single species, M. nnihasfatus Humes and Frost, 1964, 

 associated with a coral. Pontes cf. P. andrewsi Vaughan (family 

 Poritidae), in Madagascar. 



The new species from Psammocora may readily be distinguished 

 without dissection from AI. unihastatus by its shorter and more com- 

 pact body form, its shorter caudal ramus (in AI. unihastatus 3.9 times 

 longer than wide in the female, 5.7 times in the male), and its narrower 

 free segment of leg 5 in the female (in AI. unihastatus L7 times longer 

 than wide). 



AI. psammocorae is similar to M. unihastatus in several basic respects, 

 particularly the segmentation and armature of the first antenna, 

 second antenna, leg 1 in the female, leg 2, the exopod of leg 3, the 

 endopod of leg 4, and leg 5. The dift'erences seen in leg 1 of the male 

 (lack of sexual dimorphism in AI. psammocorae), in the endopod of 

 leg 3 (last segment 1,1,2, instead of 1,11,2), and in the exopod of leg 4 

 (last segment 11,1,5, instead of 111,1,5) are probably only of a specific 

 rather than generic nature. 



The mouthparts of AI. psammocorae exhibit certain detailed dif- 

 ferences from those of M. unihastatus. The mandible in the species 

 from Psammocora has an outer basal auricular expansion and a 

 relatively long terminal lash. The paragnath is elongated. The 

 first maxilla is armed with four elements. 



