558 MB. W.T. LANCHESTEK ON THE- [DeC. 3, 



considerable, aud it is therefore difficult to satisfactorily determine 

 the value of differeuces such as occur, as in the present instance, 

 in a single individual. But where the points of difference are as 

 distinctive as they are here, it does seem to me justifiable to put 

 forward a provisional name, rather as an expression of the 

 occun-ence of such variations, than as a definite opinion on the 

 constancy of these variations. For, after having served the purpose 

 of calling the attention of future systematists to the variation 

 noted, the name may readily be dropped or retained according to 

 the results arrived at by the study of more ample material. 



Most noticeable, then, in this specimen is the smoothness of the 

 carapace, a smoothness due to the general absence of teeth thereon ; 

 such teeth as are present are placed as follows : — Two large supra- 

 orbitals, each with a smaller tooth, about one-quarter the size, close 

 behind at the base; behind these again are six teeth, quite rudi- 

 mentary, forming the angular points of three contiguous transverse 

 squares on the slightly swollen gastric region. Four transverse 

 teeth, just behind the broad and deep cervical suture, in pairs, 

 i. e. two close together on each side. Two strong teeth, one-third 

 size of supraorbitals, on the anterior margin of the carapace on 

 each side, above and below the attachment of the first antennae ; 

 behind the lower of these there is a small tooth on the carapace, 

 and behind and above the upper of these, and a little further 

 back on the carapace, another small tooth, Posterior to these 

 is an oblique furrow formed by a lateral extension of the cervical 

 suture, which is continued downwards aud then forwards to a point 

 just below the antero-lateral angle of the carapace, and is here 

 very deep. On the oblique posterior border of this furrow may be 

 seen two small teeth some distance apart. 



The abdominal segments are quite smooth, except for some 

 strong punctse, the first segment only bears a furrow, broad and 

 shallo^^■, with faint traces of hairs. The telson is marked, as 

 customary in the group, with thick longitudinal ridgings, like the 

 rays of a fish's fin, in its distal two-thirds ; anterior to this are 

 many small horny spinules arranged in the arc of a circle, the 

 circumferential portion of which is delimited by a white line. The 

 uropods are armed with horny spinules on the postei'ior margin of 

 their proximal joints ; and small closely-set horny spinules are 

 ranged also along the posterior margin of the sixth abdominal 

 segment. 



As regards the colour (in formol) it may be noted that the 

 general basis is white, on the carapace, with regular brown patches, 

 \\ hich are again marbled with white. Down the middle aud on 

 each side the white basis forms three distinct M'hite stripes ; these 

 are parallel and do not form a W as in S. demani Borrad. (vide 

 Willey's Zool. lies. iv. p. 41S, aud S.polyphagus Ortmaun, Semon's 

 ' Forschuugsreise,' v. p. 10). The general basis of the abdomen is a 

 somewhat deeper white; the furrow of the first segment is brown 

 marbled with white; the hind borders of segments 1-4 have a 

 btoad brown band with two narrow Mhite bands which are nearly 



