94 



IIYDRACARINA 



genus •A^eocalonvx. Beyond doubt these plates are arranged after the same scheme, though 

 \Vaher does not give any details. In the new genus Protciclla the chitinized elements around 

 the frontal organ are united into a frontal shield, which is built up from the prae- and post- 

 frontalia, the frontale, and the dorsocentralia 1. As in so many 7'hyasiiiar, there are two 

 bristles arising from the shield. These bristles are homologous with the postocularia in the 

 Thxasinae. The praeocularia are inserted free in the soft skin in front of the shield. In the 

 construction of the dorsal surface of the body the genus Protcuila thus puts one in mind of 

 the genera Paiiisoides and Paiiisopsis among the Thyasinae (cf. Lundblad. 1''33. Figure 12 a 

 and c), though in Panisoidcs and certain Panisopsis species some of the dorsocentralia and 

 dorsolateralia are much more enlarged. 



The shape of the frontal shield in Protsiella hutchitisoiii will ]x seen from the drawing. 

 The shield is somewhat incised in front as well as behind, and the posterior margin is thick- 

 ened to fonn a callosity, whereas the rest of the shield is fairly weakly chitinized. The post- 

 ocular bristles are inserted in the lateral corners. The frontal organ is well developed and 

 divided into two regularly shaped lateral parts, with a pigment spot in each. Such a structure 

 we again meet with in some of the Thyasinae, viz., Euthyas and Thyasides (Lundblad, 1927). 



S . The maxillary organ is 278/1 long. The upper side of the rostrum is convex, and 

 the rostrum is l>ent downwards. The mandible (including the clawj measures 286/i in length. 

 The lengtli ol the extensor and flexor sides of the palp-segments are (in /n) : 



The penultimate segment ends sharply ptMUted. and the second segment is ])r()\ided 

 dorsally with rather numerous bristles, whereas otherwise the i)alp is only poorly l)eset with 

 bristles. 



The anterior two pairs of legs are short and robust and, like the two posterior ones, 

 provided with a great many strong spines, the longest of which are arranged in whorls at the 

 distal ends of the segments 3-5. The 4th leg dilYers by its considerable length from the other 

 ones, the 4th segment especially being prolonged. This segment increases in length from 

 the first to the fourth leg; the measurements for this segment in tlie difYerent legs are as 

 follows (in /^) : 



1st leg: 147; 2nd leg : 182; 3rd leg: 220; 4th leg: 392. 



The indifferently shaped epimera are widely separated into four groups. The anterior, 

 projecting corners bear tufts of long, backwardly directed bristles or hairs. 



The genital area occupies the region I^etween the pcsterior pairs of epimera. The genital 

 opening is 260/^ long and bounded at the anterior end by a supporting, chitinized body. 

 Another chitinous piece is to l)e found farther back. The genital plates are much shorter 

 than the opening, but 121/^ long, tapering" towards Ixith ends and sup])lied with rather few, 

 thinly inserted bristles, most of which arise from the median border. The genital lips inside 

 the plates are papi Hated, the papillae being very small and scattered. Lateral to the plates 

 there are many acetabula, about 24 on each side. They var}- somewhat in size and are not 

 stipitate like those in most other Prolziidac. 



