Apiil, 1900. 1 73 



that the claspers are hollow organs conmiunicating freely with the 

 general cavity of bhe abdomen, and containing fluids and fat, and even 

 more highly organized tissues. In fact the appendages, together with 

 the frame that supports them, probably represent the last larval 

 segment, the uncus (one of the chief oifices of which is, I believe, to 

 sling the end of the alimentary canal) being the representative of the 

 anal flap, and the claspers the equivalents of the last pair of prolegs. 



The first observation suggested by the figures is the extraordinary 

 contrast between the organs of spinicolella and cerasicolella and those 

 of concomitella and the rest. They form indeed two groups scarcely 

 comparable. In the former the size of the claspers is astonishing. 

 Were the whole length, from the first abdominal segment to the tip of 

 the appendages, to be divided into eight equal parts, three would go 

 to the claspers, and the remaining five to the abdomen proper, which 

 will give some idea of their actual size. They are formidable-looking 

 objects ; strikingly like a pair of jaws, and as organs of prehension it 

 would be hard to beat them. The inner surface is armed at the end 

 with a few strong teeth, and a single formidable one further back, 

 supported on a raised base ; intermixed sparingly with the teeth are 

 some stoutish hairs, not shown in the figures. The spines (c) are 

 equally remarkable. A small and insignificant base gives origin to a 

 very long and delicate filament, curiously curled at the end. The curl 

 is suggestive of pliancy and changeability of shape, but in reality the 

 filaments are of hard brittle chitin, and their ends permanently cast 

 in this curious attitude. The use of these strange bodies is highly 

 problematical. It is quite possible they may have no real use, their 

 very asyuimetry, which is sometimes extreme (see figure of concomi- 

 tella), favours this view ; besides, some of the species in the genus 

 are entirely without them, and it is difficult to believe that pairing 

 with them is less ready and effective. Widely distinct from the others, 

 the two species are perhaps more alike between themselves than are 

 any two in the concomitella group, with the exception of mespilella 

 &nd pj/riv or ella. They may, however, be distinguished readily enough 

 by attending to three points : — the first is the position of a small 

 group of teeth (marked d in the figures) ; the next, the grouping of 

 the hairs (e), which in spinicolella are arranged in small clumps of 

 three to five, and in cerasicolella in long lines of seven and eight or 

 more; and the last is the form of the bases of the spines (c), which 

 are somewhat elongated in spinicolella, and more rounded in cerasi- 

 colella. 



The seven remaining species form too a perfectly natural group, 



