292 ME. A. D. MICHAEL ON THE VAEIATIONS IN THE 



one freshly killed creature, after examining it with a number of others, so as to assure 

 myself that it was a good average specimen. I may state here, though jiossibly it 

 belongs rather to a later branch of my subject, that these spermatozoa after being 

 discharged from the mother-cell, and as found in the female, where in this species they 

 occujiy the recess in the vagina described by Winkler, have increased in size from what 

 they were in the mother-cell and have become slightly elliptical bodies of about 6 ^ to 

 7 /ti lono" diameter. There are a very large number of spermatozoa in a mother-cell in 

 this species. The large sperm-mother-cells often adhere in groups of 3 or 4 in the testis, 

 which thus seems divided into separate masses. 



In Lcelaps cuneifer, a very much smaller species, we have a nearer approach to what 

 occurs in Winkler's species : there is a single, unpaired, central testis ; but instead of 

 being globular, it is pine-shaped, and lies almost transversely in the body (PI. XXXIII. 

 fig. 30) ; from near one of the rounded angles at the base of the pine proceed two longish 

 vasa deferentia, which are of nearly even diameter throughout, and start quite suddenly 

 from the testis (fig. 31). The great accessory gland in this species, although placed as 

 in G. crassij)es and G. terrihilis, is different in form (fig. 31, gla). It widens out 

 towards its distal extremity and is slightly flattened ; but its hind margin is deeply 

 indented, so that the posterior portion of the organ becomes bifurcate, each side being a 

 large rounded lobe. In this species the testis is, as in G. terribilis, constituted of large 

 sperm-mother-cells, gradually increasing in size (flg. 32) ; they are much smaller 

 actually than those of G. terribilis, but are large relatively to tlie size of the sjDecies. 

 They ax-e not so tightly packed as in G. terrihilis, and are considerably diilerent in the 

 average class of form, as may be seen from the figures ; the individual spermatozoa are 

 larger in j)i'oportion and less numerous, the nucleus seems to disappear at an earlier 

 stage, and the mother-cell is less smooth and transparent. 



In Lcelaps hevis the process which we have seen commencing in the last species by 

 the bifurcation of the hinder portion of the accessory gland has gone vastly further ; 

 here w^e find (fig. 33) not one central gland, but two totally separate elliptical glands, 

 discharging by extremely short ducts, which coalesce only where they enter into the 

 ductus ejaculatorius. The same arrangement is found in Hccmogamasus hirsutns and 

 in H. horridus (see PI. XXXV. fig. 72, which is a transverse section cutting the two 

 accessory glands {gla) just at the point where the large columnar secreting-cells, which 

 form the hinder parts of the glands, are fading into the looser reticulate tissue found 

 in their anterior portions, and which appears more adapted to the collection and storage of 

 secretion). A longitudinal section through the testis of Lcelaps kevis is drawn at fig. 3i 

 (PI. XXXIII. ). It wall be seen that the formation of the ripe sperm-mother-cells is 

 somewhat different from that in the species above described ; the spermatozoa are less 

 distinctly formed, and lie in scattered amoeboid masses in a looser and more reticulated 

 substance. This drawing was very carefully made from the actual section, but in con- 

 sequence of the very small number of specimens which I was able to obtain I could not 

 investigate this species as fully as I should have liked. 



What struck me as an interesting case of spermatogenesis, which I believe is novel, 

 in the Acarina at all events, although it may possibly bear some slight analogy to 



