90 . Memoirs of the Indian Museum. [Vol,. IV, 



The last three thoracic somites (fig. yy) bear submedian and intermediate carinae ; 

 the former are often obscure or quite obsolete, while the latter are more prominent 

 and in large specimens of both öexes terminate posteriorly in spines. On either side 

 of the inferioi surface of the fifth somite there is a broad but thin downwardly-directed 

 lobe, which is often anteriorly acute or spinous ; from its base a deep and wide 

 groove runs upwards dividing the somite transversely into two unequal portions. The 

 lateral margins of the sixth somite are produced to an acute posterior point ; anteriorly 

 a very short, broad and ill-defined process represents all that remains of the prominent 

 lobe found in the species of the 5. nepa group. The margins of the seventh somite 

 resemble those of the sixth, but the anterior process is never represented by more than 

 a slight angulation. 



There are eight longitudinal carinae on the first five abdominal somites and six on 

 the sixth. Those of the submedian pair are often very faintly marked except on the last 

 somite where they appear as strong blunt ridges. The following carinae end in spines :- 

 Carinae. Abdominal somites. 



Submedian . . . . . . 6. 1 



Intermediate .. .. .. (i)' 2 (2) 5 3, 4, 5, 6. 



Lateral .. .. .. .. 1,2,3,4,5,6. 



Marginal .. .. .. 1,2,3,4,5. 



The telson is thick and massive. The median carina has the form of a strong blunt 

 ridge which, except in very large examples (where it appears to have been worn away), 

 terminates posteriorly in a spine. The ridge is continued beyond the spine and, as a 

 rule, projects as a median tubercle on the distal margin. On either side of the median 

 crest are a few oblique rows of pits. The six marginal teeth are sharp and prominent 

 and in old specimens somewhat rugose, each forming the termination of a short rounded 

 carina. There is no praelateral denticle. In large specimens of both sexes the entire 

 margin of the telson is strongly swollen and tends to obscure the denticles. Of the 

 latter there are four to six submedian, seven to thirteen (usually nine or ten) inter- 

 mediate and one lateral. The post-anal carina is distinct and in old specimens more 

 or less tuberculate. 



In the bifurcate process from the base of the uropod the inner spine is about twice 

 the length of the outer and bears a small lobe on its outer margin near the end of its 

 distal half. 



Among Indo-pacific species Squilla raphidea is peculiar in that the margins of the 

 telson are inflated in large specimens of both sexes. The angled external edge of the 

 raptorial dactylus, characteristic of the mature male, is, as a rule, well-marked in all 

 examples of that sex measuring 190 mm. or more in length ; but one male of 190 mm. 

 is remarkable for the entire absence of this feature. 



Balss has described a variety under the name, var. africana, distinguished by 

 the form of the rostrum, the sharpness of the submedian carinae of the post- abdomen 

 and the thickened teeth and denticles on the margin of the telson. The rostra of 



1 Often worn down and obsolete in very large specimens. 

 * In large specimens only. 



