igo8.] R. E. lyivOYD : Bathynomus giganteus. 99 



invariably present (numbered i — 5, pi. x, fig. 3), It will be seen from this figure that 

 the small oval plate indicated by the number 2 is in the position of the muscle- 

 attached ''fossette" of the American specimen (/.s., pi. vi, fig. i, of Bouvier's 

 monograph). The larger plate, 5, which is entirely on the posterior or hidden surface 

 but articulates with the prominent fourth plate, is not represented at all in the figures 

 of the American specimen. 



M. Bouvier's work is such that we can eliminate the possibility of error in his 

 rendering of the structures in question. We must conclude, therefore, that the Indian 

 form of Bathynomus differs from the American in this respect. That these structures 

 are prone to vary is shown by comparing the same author's figures of the American 

 specimen with that of the Japanese species, B. döderleini. 



IV.— THE DISTRIBUTION OF BATHYNOMUS GIGANTEUS IN 



INDIAN SEAS. 



Nine specimens of this large Isopod have been taken by the " Investigator " from 

 six separate stations. The following is a list of the stations from which they were 

 obtained : — 



I. Station 105, lyat. 15° 2' N., Ivong. 72° 34' E., I^accadive sea, in 740 fathoms. 

 Three immature female specimens were obtained, measuring 160, 195 and 

 200 mm., respectively. These were recorded by Wood-Mason and Alcock 

 (3)- 

 II. Station 145, I^at. 15° 5' N., Ivong. 72° 38' 10" E., from the lyaccadive sea, in 

 692 fathoms. " One small specimen " was obtained. The length and sex 

 were not recorded, and the specimen has passed out of the Indian Museum. 

 The naturalist's notes at the time of its capture record the fact that Station 

 145 was carefully chosen as close as possible to the previously successful 

 Station 105, with the special intention of obtaining more specimens of 

 Bathynomus. Exceptional good fortune must have attended the successful 

 second attempt. 



III. Station 256, Lat. 9° 32' N., I,ong. 80° 59' 30'' E., off north-east coast of 



Ceylon, in 594 — 225 fathoms (a very steep sea bottom). One large mature 

 male with copulatory stylets : this is the largest recorded specimen ; it 

 measures 270 mm. by 118 mm. 

 It was referred to by Alcock in '' A Naturalist in Indian Seas," page 271. 



IV. Station 358, I^at. 15"- 55' 30" N., I,ong. 52° 38' 30'' E., off south coast of 



Arabia, in 585 fathoms. Two specimens; an immature male measuring 55 

 by 130 mm., and an immature female measuring 83 by 184 mm. previously 

 recorded by the author (24) . 



V. Station 371, I,at. 12° 18' 46" N., I^ong. 74° 5' 29'' E., Laccadive sea off west 

 coast of Madras, in 580 — 540 fathoms. An immature female measuring 

 193 by 89 mm. 



