304 ME. A. D. MICHAEL ON THE VAKIATIONS IN THE 



of the cornu is not closed, but a long fine tube runs from it to the camera spermatis ; 

 this tube also is shown extended in the figure, but in situ is wound round the sacculus 

 and is difficult to see. 



Holotaspis marginatus is a rather large and powerful species ; in it the lyrate organ 

 has a rather different appearance from what it has in the above-described species ; the 

 arms are comparatively very thin, but have sharply clavate ends (PL XXXIV. fig. 60, ol). 

 The cellulation of these arms is apparently similar to that of other species, except that I 

 am not able to detect the nuclei which are so very conspicuous in the others. On the other 

 hand, the camera spermatis (cms) is extremely large, and its surface seems to be composed 

 of cells similar to those of the arms, which is unusual ; it appears as if it had taken upon 

 itself part of the function of the arms in consequence of the small size of the latter. 

 The sacculus is of the usual class of tissue, but is a long roughly-elliptical sac, with 

 its long diameter transverse to the body. The cornu is not at all of the usual type ; it 

 is short, wide, and rather fleshy, and passes straight to the uuderside of the camera 

 spermatis. In this species there appears a new complication of the organs which is far 

 from easy to understand ; the ringed tubes (ta), instead of terminating at or shortly after 

 their entrance into the sacculus, continue in an almost straight line nearly to the middle 

 of that organ, and there the two are joined, within the sacculus, by a small oval sac 

 which communicates with each tubulus. There is, springing from the middle of this 

 inner sac, a short, straight, and extremely fine tube running to the cornu. 



Fig. 61 represents the sacculus of a small species found in Tyrol, and bearing 

 considerable external resemblance to Holotaspis montivagus, but which I am unable to 

 identify, because I dissected the one or two specimens which I found. I mention it 

 because the structure of the organs I am describing is in some respects intermediate 

 between the species last described and the next. Here the sacculus is rather small and 

 bag-shaped ; it stands free without cornu or rami or any apparent communication with 

 the camera spermatis or the ovary ; its only attachment seeming to be the ringed tubes 

 which enter it at the corners, and terminate by bulbous endings within the sacculus. 



Lmlaps cuneifer (fig. 62) is constructed much on the same model ; the sacculus is free, 

 without cornu or rami ; the ringed tubes, however, enter close together on the underside 

 of the sacculus, and terminate where they enter it without continuing inside. 



Holotaspis montivagus is the species where neither Prof. Berlese, who originally 

 described it, nor I have ever found the male. I have considerable doubt whether the 

 mode of classification, which includes this and H. marginatus in the same genus, be not 

 an artificial one ; but this is not the place to discuss that question. In this species 

 there is a new and puzzling complication ; it seems to partake of some of the characters 

 of Holotaspis marginatus and some of those of Z,a?laps cuneifer. The lyrate organ 

 (fig. 63, ol) is large and well-developed; it shows the ordinary cellulation with strongly- 

 marked nuclei ; these extend on to a portion of the exterior of the camera sperrnatis, but 

 not all over it. The sacculus (sa) is rather small and globular ; it is entirely free, not 

 attached except by the ringed tubes ; these enter the sacculus as in H. marginatus, and 

 continue until near the centre ; but there, instead of both terminating in a single oval 

 sac as in H. marginatus, each ringed tube ends in a little hollow ball with rather 



