220 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



CERATOMYSIS, gen. nov. 



Cephalothorax robust. Carapace short (leaving the last two segments of the 

 thorax exposed), spinose ; frontal margin truncate, not forming a rostrum, armed 

 at the external angles with a pair of long horn-like spines ; a conspicuous notch 

 at the anterior end of the lateral margin serving as an excurrent orifice from 

 the respiratory chamber. Abdomen slender, cylindrical, spinose ; sixth seg- 

 ment not much longer than the fifth. Eyes absent, their stalks taking the 

 form of slender styles, whose tips are soft and delicate, perhaps serving as 

 tactile organs. Antennular peduncle rather short ; flagella much longer than 

 the peduncle, flattened and fringed with long setae on their margins. Antennal 

 scale linear, ciliated on both margins. Mandibular palpi reaching beyond the 

 antennular peduncle ; terminal segment long oval, margins fringed with long 

 setse. First maxillipeds devoid of an exopod. Distal segment of second max- 

 illipeds oval, ciliate. Legs long and slender, propodi not segmented. Seven 

 pairs of incubatory lamellae in the female. Fifth and sixth abdominal limbs 

 elongated in the female. Telson linear, setose on the margin. Both branches 

 of the uropods linear, setose on each margin, subequal, shorter than the telson ; 

 outer branch not divided by a transverse suture. 



Ceratomysis spinosa, sp. nov. 



In front of the cervical groove are three long erect spines in the median line, 

 the foremost of which is on the frontal margin ; there is, besides, a spine on 

 each side of the carapace in a transverse line with the middle one of the median 

 row ; behind the cervical groove there is one spine in the median line near the 

 posterior margin of the carapace, two on each side of the tongue-shaped dorsal 

 area, and a long row of six on each side, in line with the lateral spines of the 

 gastric area. Abdomen armed with five longitudinal rows of spines (one me- 

 dian, four paired and lateral). Telson very long and narrow, nearly equalling 

 the length of the remaining portion of the abdomen. 



Color in life, milk-white. 



Length, 36 mm. ; carapace, 9 mm. 



Station 3357. 782 fathoms. 1 female. 



