294 



e„ Fourth abdominal somite with three lateral parallel carinae 



on each side Rathbuni de Man 



ó 2 First lateral carina of carapace with 4 teeth, 2 nd lateral with 

 3 to 6. 

 Antennal scale much longer than broad. 

 ^"j Second lateral carina of carapace with 5 or 6 teeth, marginal 



with 3; median carina of 2 nd abdominal tergum bispinous andamanensis W.-Mas. 

 (A. Alcock, 1. c, 1901, p. 121.) 



e, Second lateral carina of carapace with 3 teeth, marginal 



with 2 ; median carina of 2 nd abdominal tergum unispinous bengalensis W.-Mas. 

 (A. Alcock, 1. c. 1901, p. 122.) 



1. Aegeon pennata (Batej. PI. XXIV, Fig. 70 — ~ t od. 



Pontocaris pennata C. Spence Bate, Report Challenger Macrura, 1888, p. 499, PI. XCI. 

 Pontocar is pennata A. E. Ortmann, in: Proc. Acad. Nat. Sciences Philadelphia 1895, p. 175. 

 ? Aègeon affine A. Alcock, A'descript. Catal. Indian Deep-Sea Crustacea, Calcutta 1901, p. 118. 

 Aegeon pennata H. Balss, in: Sitzungsber. Kais. Akad. Wiss. Wien, N° IX, Jahrg. 1914, p. 137. 

 Aegeon obsoletum H. Balss, Ostasiatische Decapoden II. Die Natantia und Reptantia. München, 



1914, p. 70, Taf. I, fig. 3. 

 Aegeon pennata H. Balss, Die Decapoden des Roten Meeres. I. Macruren. Wien 191 5, p. 32. 

 Aegeon pennata Stanley Kemp, Records of the Indian Museum, Vol. XII, Part VIII, December 



1916, Calcutta 1916, p. 376. 

 Illustrations of the Zoology of the "Investigator"', PI. LI, figs. 3, 3^ and 4, 



Stat. 306. Febr. 8, 1900. 8°27'S., 122°S4-'.S E. Lobetobi Strait. 247 m. Bottom sandy mud. 



2 males and 2 females, one of which is ovigerous. 

 Stat. 312. Febr. 14, 1900. 8° 19' S., ii7°4i'E. Saleh Bay, Sumbawa. 274 m. Bottom fine, 



sandy mud. 2 males and 1 adult female without eggs. 



These specimens certainly belong to the typical species described by Spence Bate. 

 Though Aegeon affinis Alcock and A. pennata (Bate) are considered as specifically identical 

 by Dr. Calman, who was enabled to compare co-types of the former with the three Challenger 

 types of the latter (S. Kemp, 1. c), in my opinion, however, on account of the following 

 observations the species from off Bombay should be considered at least as a distinct local 

 variety affinis of A. pennata (Bate). In the first place I may call attention to the fact that the 

 Challenger types are young animals: according to Spence Bate, indeed, the entire length was 

 only 24 mm. (carapace 7 mm., abdomen 17 mm.), whereas the ovigerous female (Fig. 70) from 

 Stat. 306 measures 43 mm., being almost twice as long. The adult female from Stat. 312 has 

 the same size, while the largest male is 37 mm. long (carapace 11 mm., abdomen 26 mm.), 

 the male presenting, like in other species, a somewhat smaller size than the female. When the 

 present adult specimens are compared with the figures 3 and 4 of Plate LI of the "Illustrations", 

 the body appears decidedly less broad in proportion to the length than in the species from 

 off Bombay: while in Fig. 3 (the female) the width of the 2 nd abdominal somite is just one- 

 fourth and in Fig. 4 (the male) one-fifth the whole length from the tip of the rostrum to 

 that of the telson, in the three females of the typical species it is only one-fifth and in the 

 males (Fig. 70^7) only about one-sixth the entire length. In Aegeon affinis all the carinae of 



