170 



DISCOVERY REPORTS 



d e 



Text-fig. 12. Macrochiridotheastebbingi. (a) Antenna, x 20. (6) Third pereiopod, x 12. (c) First pereiopod, x 12. (^)Anten- 

 nule, X 20. (e) Maxilliped (left), x 30. (/) Cutting edge of left mandible, x 30. [g) Second pereiopod, x 12. {h) Second 

 pereiopod, x 17. 



Genus Macrochiridothea Ohlin, 1901 



Macrochiridothea stebbingi Ohlin, 1901 (Text-fig. 12, a-h) 



Macrochiridothea stebbingi Ohlin, 1901, pp. 289-91, pi. xxii, fig. 9. 



M. stebbingi yar. midtitiiherculata, Nordenstam, 1933, pp. 106-8 and 112, pi. i, fig. 7. 



Occurrence. St. WS 88: 6. iv. 27, 54° 00' 00" S., 64° 57' 30" W., 118 m., i ?. St. WS 772: 30. x. 31, 45° 13' S., 

 (30° 00' W. to 45^ 13-8' S., 60° 00-5' W., 309-162 m., 5 specimens, i $ (non-breeding). 



The genus has the characters of the subfamily. 



The largest specimen in this collection is a female measuring 9-5 mm. in length and 4 mm. in 

 greatest breadth; the tubercles on the dorsal surface of the body, though similar in distribution, were 

 less pronounced than those on the remaining specimens. 



This species was first described by Ohlin (1901, p. 289) from a single female measuring 7 mm. in 

 length. In this description he stated that the head is nearly as long as the first three segments of the 

 mesosome, and that the pereion segments are of ' about the same length ', but his figure (pi. xxii, 9a) 

 shows the second pereion somite to be twice as long as the middle of the first, and the lateral margins 

 of the first about three times the length of its centre. Assuming that Ohlin's figure is inaccurate, then 

 the length of the middle of the first pereion somite should be doubled to make it equal to that of the 

 second somite. This would result in a reduction in the ratio, length of the middle of the somite: 

 its lateral margins, i.e. from 1:3 to 1:1-5; this change would bring the proportions more or less into 

 line with those given by Nordenstam for his variety multituberciilata, and also with the specimens in 

 the Discovery collections. If the length of the central part of the head in Ohlin's figure was shortened 

 to allow for the necessary increase in the length of the first pereion segment, this would lessen the 



