Chilton. — On the Changes in Form of Nerocila. 69 



taining four specimens, of which one was an undeveloped 

 female, and another a fully-developed female with large incu- 

 batory pouch, and the other two also females with pouches 

 developed, but in other respects intermediate stages between 

 the first and second. It is the first form that has been de- 

 scribed by Schiodte a.nd Meinert as Nerocila nova-zelandice, 

 and is by them spoken of as " virgo." Their detailed descrip- 

 tion applies very closely to specimens of this stage, so that I 

 have no hesitation in giving their name as a synonym. These 

 a,uthors have given the differences between the "virgo" and 

 the adult female in other species of Nerocila, but the material 

 at then- command evidently did not enable them to do this for 

 this particular species ; and, as their work is not easily acces- 

 sible to students in New Zealand," I propose to give here a 

 description of the " virgo," and afterwards to compare it with 

 the fully-developed female. 



The body is narrow-oval, about three times as long as 

 broad. The head is large, suborbicular, broader than long, 

 slightly immersed in the first segment of the thorax, front 

 rounded or with very sliglit indication of an angle in the 

 centre. The eyes are of fair size and quite distinct, sub- 

 pentagonal or subhexagonal in shape. The 1st pair of 

 antennae are somewhat compressed ; those of the 2nd pair 

 much more slender, terete, 11-jointed. The posterior angles 

 of the first five thoracic segments are not produced, and are 

 rounded or obtuse ; those of the 6th and 7th segments are 

 obtuse and very slightly produced backwards. The first three 

 pairs of epimera are rectangular, overlapping, rounded pos- 

 teriorly ; the last three are somewhat acute posteriorly ; the 

 5th more produced than the 4th, and the 6th equally more so 

 than the -jth. Last pah- of thoracic legs a little longer and 

 more slender than the others, and with a few spines on the 

 meros, carpus, and propodos. Abdomen exposed — that is, not 

 covered by the thorax ; much longer than broad ; 1st segment 

 shorter than the otliers ; 2nd, 3rd, and Ith subequal ; oth a 

 little longer : pleural portions of the 1st and 2nd segments 

 only slightly produced. Telson cordate, as long as the other 

 segments of the abdomen together, about as broad as long, 

 somewhat sharply rounded at the extremity. Uropoda with 

 the basal joint expanded distally, and slightly produced at the 

 inner distal angle ; inner branch broad and flat, Avidening a 

 little distally, obliquely truncate, a very small tooth at the 

 inner angle, the truncate extremity slightly sinuate, outer 

 angle reaching a little beyond the extremity of the abdomen ; 

 outer branch much narrower and somewhat longer, widest 

 about the middle, flat, extremity subacute. 



* r am indebted to INIr. Thomson for the loan of his copy. 



