the Early Stages o/Paltostoma scliiiieri. 187 



whole arrangerneut greatly resembles that figured by Miiller 

 (op. cit. pi. vi. fig. 7, and p. 73). 



The part of the dorsal surface behind the cephalic areas is 

 divided into two portions by a transverse Hue of dark spots, 

 which are seen under a higli power to consist of small smooth 

 areas set like islands among the dense rugie of the general 

 surface. The anterior of these portions bears a pair of 

 very conspicuous eye-like spots (fig. 1, e.s.), situated one ou 

 either side, some distance behind the division between the 

 lateral and intermediate areas. Each spot consists of a dark 

 body, the chitin immediately surrounding which is pale and 

 almost colourless. F. Muller [op. cit. p. 51, pi. iv. fig. 10) 

 describes and figures organs of like nature in his larva, and 

 comments on their resemblance to eyes. They must not 

 be confounded with the true visual organs described above. 

 The writer is inclined to believe that these dark spots are the 

 (as yet functionless) first pair of spiracles ; Muller describes 

 these [op. cit. pp. 67, 70) as situated on the dorsal side of 

 the cephalothorax, but he docs not appear to state whethei' 

 they are identical with the eye-like s])ots or not. Immedi- 

 ately behind the eye-like spots, and in front of the transverse 

 line, are two deep p'^^ (P'- IX. fig. \, p.) projecting down, 

 wards into tlie interior of the body. The posterior part of 

 the cephalothorax (behind the transverse line) bears two 

 conical spines, similar to those on the succeeding segments • 

 and the hind margin bears a series of spines on eitlier side 

 behind the lateral process. Ventrally, the cephalothoracic 

 segment is ciliate towards tlie sides. 



Sef/ments 2-5. — There is a series of conical spines, short 

 and sharp, along the front margins of the projecting lateral 

 portions of each segment ; and a less regular series along the 

 hind margins of these lateral portions. These anterior and 

 posterior marginal series are continued across the dorsum 

 of the segment as two transverse series, each consisting of 

 about 4-6 spines, widely spaced out, and when viewed from 

 directly above appearing as dark spots. There are also 

 scattered smaller spines on the projecting lateral parts of the 

 segment. Ventrally, the surface is smooth, except for a 

 rugulose-spinulose area on either side at the base of the 

 lateral process (PI. IX. fig. 2). 



The lateral processes (both of these and of the sixth and 

 cephalothoracic segments) are simple, pediform, bearing 

 long fine ciliae dor^ially except at the base. There are no 

 spines or setae exceeding the ciliae in length, as in some 

 genera, but in balsam-mounts each lateral process is seen to 

 bear a series of several spines shorter than the cilije and 

 concealed from ordinary view among these. A^cntrally the 



