17 



peduncle especially becomes very short and the radiating spines reduced in number. The side 

 of the carapace is crossed by a diagonal line of close-set simple spinules running backwards 

 and upwards from the antero-lateral corner, near which its spinules become long and slender. 

 Below this line none of the above described compound spines are found, their place being taken 

 by scattered simple spines. A little way above the lower margin is a horizontal but slightly 

 sinuous serrated ridge which near the antero-lateral corner becomes broken up into a row of 

 spines. Between the spines above described the whole surface of the carapace is beset with 

 minute spiniform points regularly disposed and rather widely spaced. On the rostrum these 

 minute spinules are more numerous and closely set. 



The free thoracic somites diminish rapidly in height and in width in passing backwards. 

 The first is very short but completely exposed. The line of separation between the second and 

 third is not very strongly marked, suggesting that these two somites are immovably united. 

 All the somites have the surface beset with spiniform points with small spines scattered 

 among them. 



The abdomen is slender and, including the long telson, a little longer than the cephalo- 

 thoracic region. The somites are subcylindrical and beset with small spines and spiniform points. 

 The telson (PI. II, fig. 25), including its terminal spine, is about five times the length of the 

 last somite and nearly as long as the last three somites together. Except close to the base, 

 where it widens a little and where the anus is situated, the telson is narrow, nearly 20 times 

 as long as broad, and the sub-parallel sides of the post-anal part are strongly dentated for the 

 greater part of their length. Near the distal end are three pairs of lateral spines and the tip 

 bears three spines, the median one twice as long as the other two and about one-sixth of the 

 total length of the telson. 



The antennules (PI. II, fig. 19) are remarkably long and stout, almost pediform in 

 appearance, about -7, of the length of the carapace. The first segment of the peduncle is equal 

 in length to the other two, which are subequal. The external flagellum is V; of the length of 

 the peduncle and is very stout. It is composed of five segments, the terminal one being very 

 minute. The third and fourth segments are subequal, together equal in length to the first and 

 each a little longer than the second. The inner flagellum (PI. II, fig. 19a) is very minute, 

 hardly one sixth as long as the first segment of the outer flagellum. It is composed of three 

 segments, the first and second subequal and the last minute. The segments of the peduncle and 

 of the outer flagellum are closely beset with minute spiniform granules among which on the 

 proximal segment are a few longer spines. 



The antenna (PI. II, fig. 17) could not be fully seen without dissection but it possesses 

 a long, styliform terminal segment the lower edge of which and of the only other segment 

 which is visible carries a few small spines. 



The third maxillipeds (PI. II, fig. 20) are more pediform than in any other Cumacean 

 known to me. The basis is one-half the length of the limb, narrowing gradually towards the distal 

 end with the outer angle not at all produced but bearing several very long plumose setai; the 

 inner margin is minutely serrated distally. The ischium is very short, the merus is produced 

 and rounded externally. The carpus is nearly as long as the next two segments together. The 



SIBOGA-EXPEDITIE XXXVI. 3 



