HYDRACARINA 



97 



Protzia or Calonyx, i.e. being dilated at the apex and consisting of a main claw and some 

 lateral teeth. It is interesting to find that we are able to draw parallel lines of develop- 

 ment within both families (claws, frontal organ, chitinization of body). Even if some of 

 the characters are to be regarded as being independently acquired by the two families, some 

 others may well be of common origin. In this connection it is of a great interest to draw atten- 

 tion to a paper of Motas (1929) in which he has described the larva of Calonyx brcvipalpis. 

 His drawings, compared with the figures given by other authors and the present writer ( 1927), 

 of the larvae of some Thyasinae and Hydryphantinac again reveal the fact that all these 

 three groups undoubtedly are nearly allied to one another. However, the declaration of Motas 

 (1. c, p. 261) that the Protsiidac occupy an intermediate position between the Thyasinae and 

 Hydryphantinae seems to me to require further evidence. I think it is better to join, as 

 hitherto, the subfamilies Thyasinae and Hydryphantinae into the same family, Hydryphan- 

 tidac, and to place the Protsiidac in the vicinity of the Hydryphantidae. 



4. Calonyx montanus sp. n. 



(5 . Length of body about 965/it. Skin without chitinous plates. Frontal organ very 

 small, hardly bigger than a skin-papilla and lying some distance behind a line connecting the 

 composite eyes. The organ looks like a rounded, circular papilla, which projects a little more 

 over the skin-surface than do the ordinary papillae. The row of dorsoglandularia is char- 

 acterized by the third dorsoglandulare having been much displaced in lateral direction, so 

 that the distance between the two glands of that pair is distinctly longer than that between 

 the eyes. 



Length of maxillary organ 275/i. Seen from the side the rostrum is rather flat. The 

 ventral surface projects angularly over the rest of the rostrum and the dorsal side is undu- 

 lated. The mandible is 264/<. long from the base to the tip of the membrane, which tapers and 

 is sharply pointed at the end. The claw is 89/* long. The bristles nn the palpi are few in 

 number and the lengths of the palp-segments are (in ft) : 



The projection at the end of the fourth segment is long and slender, with the tip bent 

 ventrally. 



The bristles on the epimera are few and principally restricted to the lateral, anterior 

 corners of the first three pairs. The first pair has a forward protruding corner, bearing 

 about 10 rather short, stout, more or less spine-like bristles; on the second and third pairs there 

 are about 4-5 bristles. The suture between the first and second epimera vanishes before reach- 

 ing the median border. The greatest length of the anterior group of epimera is 268/u, that of 

 the posterior group 246^. In the third epinieron the anterior and median borders form 

 together a continuously curved arc, not being angularly bent so as to constitute well- 

 distinguished anterior and median borders, as in the following species. 



The last segment in all legs is considerably thickened toward the distal end, which is pro- 

 vided with two strong claws of different lengths. Each claw consists of a central tooth of 



