BORRADAILE— ON C ABIDES FROM THE WESTERN INDIAN OCEAN 399 



of antennule and antenna are broken short in the specimen. The third maxilliped 

 reaches more than half-way along the antennal scale. The first leg is simple and 

 sparsely hairy and barely falls short of the end of the third maxiUiped. The second 

 leg reaches the end of the first ; its wxist is nine-jointed, the first five joints being 

 longer and less distinct than the rest. The legs of the last three i^coirs are missing 

 from the specimen. The third abdominal tergum is convex behind, but not produced 

 into a spine. The sixth abdominal segment is longer than the fourth and fifth together. 

 The telson is missing from the specimen. 



Length of specimen from tip of rostrum to tip of uropods 49 mm. 



The species appears to be related to P. martins A. M.-Edwards, 1883, and P. ensis, 

 (A. M.-Edwards), 1881. 



A single female specimen was taken at a depth of 200 fathoms in the Western 

 Indian Ocean. 



Genus Heterocarpus. 



3. Heterocarpus unicarinatus Borradaile, 1915 (Plate 58, fig. 2). 



Ann. Mag. Nat. Hist. (8), xv. p. 208. 



A specimen taken in 637 — 665 fathoms near Providence Island is closely related 

 to H. longirostris MacGilchrist, 1905 [Ann. Mag. N. H. (8), xv. p. 237] but distinguished 

 by the loss of the hinder three-quarters of the antennal carina, of which the forepart 

 is present though not sharply formed. The specimen is a good deal damaged, and may 

 have presented other differences from H. longirostris. It measures 92 mm. to the tip 

 of the rostrum, which is broken. Provisionally, at least, it deserves specific recognition. 



4. Heterocarpus affinis Borradaile, 1915. 



Ann. Mag. Nat. Hist. (8), xv. p. 208. 



Specimens taken in 300 — 500 fathoms near Saya de Malha are nearly related to 

 H. alphonsi Bate, 1888, but show the following points of difference : (1) the rosti-um 

 is much more strongly upcurved, and has three teeth on the carapace behind the 

 orbit, (2) there are fewer joints in the wrists of the second legs (26 and 9, as against 

 40 and 11), (3) the walking legs considerably outreach the antennal scale. The telson 

 bears five pairs of spines on the dorsal surface and three pairs at the end. The longest 

 specimen is 12 cm. in length, including the rostrum. 



Subfamily Thal ASSOC arin^. 



Genus Thalassocaris. 



5. Thalassocaris crinitus (Dana), 1852. 



Regulus crinitus, Dana, U. S. Explor. Exped. Crust i. p. 599 ; Atlas, PL 39, fig. 6. 



The rostrum of this species may be somewhat longer than in the specimen figured 

 by Dana, and the rostral formula varies within the limits ^=^. 



Specimens were taken in various depths down to 80 fathoms at Amirante I. 

 Cargados Carajos, the Maldives, Saya de Malha, and the Seychelles. 



