A GENUS OF THE FAMILY SEEGESTID^. 



221 



First maxilliped (PL 16. fig- 7) resembling that o£ Sergestes, especially in 

 the large size of the distal endite^ which^ however, does not extend so far as 

 the tip of the exopod ; the endopod is composed of four distinct segnients. 



Sesond maxilliped (fig. 8) distinctly of the Sergestid type, in the absence of 

 exopod and the lengthening of the distal segments. 



Third maxilliped (fig. 9) also of Sergestid type in its great size — it is 

 longer by about two-thirds than the carapace, and extends well beyond the 

 antennular peduncle — the absence of exopod, and the subdivision of the 

 two distal segments, the terminal into four and the penultimate into three 

 segments ; it is strongly spinose. 



First three pairs of legs (figs. 10-12) increasing successively in length and 

 slenderness, all with well-developed chaise. On the under side of the propodus 

 of the first pair is a group of pectinate spines opposed to a similar group on 

 the carpus*; a trace of a'similar arrangement is observable in the second pair. 

 Propodus of third pair at least ten times as long as wide and nearly three- 

 fourths as long as carpus. 



Last two pairs of legs (figs. 13 & 14) each with the normal number of seven 

 segments, the dactylus being short and slightly curved ; the other segments 

 are flattened, the ischium and merus fringed with very long setse on both 

 margins, the carpus and propodus only on the inner margin. 



The pleopods of the first pair carry a petasma (figs. 15 & 16), the middle lobe 

 of which has the terminal area beset with numerous invaginated hooks like 

 those figured by S. I. Smith in Sergestes robustus. The remaining pleopods 

 are biramous ; those of the second pair have a spinose appendix masculina. 



The uropods have the exopod longer than the endopod, which, again, 

 longer than the telson ; the marginal tooth of the exopod is about one-sixth 

 of the total length from the tip. 



The branchial system is much reduced. Unfortunately, the method of 

 preservation (formalin followed by spirit) has left the branchiae very trans- 

 parent and difiicult to see. It is possible, therefore, that one or two of the 

 vestigial branchige may have been overlooked, but, with this reservation, 

 the formula may be given as follows : — 



1 mxp. i. 



mxp. 2, 



mxp. 3. 



v\ 1- 



per. 2. per. 3. 



per, 4. 



per. 5. 



Pleurobranchiae 



— 



p 



1+r 



1+1- 



l+i- i 1 + 1- 



2 





Artlirobrancliife 



— 



— 



— 



— 





— 



- 



— 



Podobranchise 



ep. 



1+ep. 



— 



— 





— 



— 



— 



* Coutiere lias called attention to a similar apparatus in various Caridea and Penseidge 

 '(C. E. Acad. Sci. Paris, cxli. p. 220, ]905). It has not been observed in Sergestidse. 



