250 SCALPELLTJM ORNATUM, 



is longer than the other two ; of these two, the one on 

 the same side with the notch, is a little longer than the 

 other. The spines on the first and second pair of limbs 

 are considerably shorter than those on the third pair, and 

 these latter, are a little shorter than those on the fourth 

 or posterior pair. Hence, the spines on the thoracic 

 limbs, compared with those of S. vulgar e, present consi- 

 derable differences, both in their relative and absolute 

 dimensions. The abdominal lobe is in proportion rather 

 shorter ; its end is less abruptly truncated, and supports 

 a row of, I believe, six moderately long, and basally 

 thick spines ; these spines are not so long as those sur- 

 mounting the fourth pair of limbs. On both lateral 

 margins of the abdomen, rather on the ventral face, there 

 is a row of, I believe, seven long spines, but it is very diffi- 

 cult to count the spines in specimens which have been 

 once dried. I was able to distinguish that the two lower 

 pair of spines on the ventral surface, are seated a little 

 way one below and within the other, as in JS>. vulgar e. 

 The abdominal spines altogether form quite a brush, and 

 there are certainly several more than in S. vulgare, and 

 those on the two sides are much longer. 



Antennce. — The disc is hoof-like, with the upper sur- 

 face forming a straight line with the upper edge of the 

 basal segment ; the apex is pointed and clothed with some 

 fine down ; there is a single spine pointing backwards, 

 which rises from the lower flat surface. The ultimate 

 segment was hidden in laminae of cement; and I was 

 not able to make out its structure. There is a single 

 spine on the outer edge of the basal segment, in the 

 usual position. The entire length of the limb, measured 

 from the end of the disc to the further margin of the basal 

 articulation, is t£ths of an inch ; measured to the inner 

 margin, it is ^ths of an inch ; the disc itself is ^ths of 

 an inch long ; these measurements differ a little both ab- 

 solutely and proportionally, compared with those of the 

 antennae of 8. vulgare. 



Cavities in the Scuta of the Female for the reception 



