ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
581 
again, are connected with one another by a substance, traverse the whole 
of the flagellum of the spermatozoon from the beginning to the end of 
the axial filament. These fibrils are the contractile elements, and they 
have exactly the same relations as in the spermatozoa of other Vertebrates 
and of Invertebrates. 
The relations of the axial cord to the neck vary considerably. In 
some, as in the Rat, the terminal knob is continuous with the anterior 
limit of the investment of the connecting piece ; no “ neck-piece ” is 
therefore present, and the “neck” is only occupied by connecting 
substance. In most Mammals the anterior end of the axial cord passes 
freely through the “ neck ” as a “ neck-piece,” and is inserted, by means 
of its terminal knob, in the pit at the hinder edge of the head by means 
of a very small quantity of connecting substance. In other species, 
lastly, the “neck-piece” of the axial cord is divided into its two halves 
in the “ neck ” itself ; these are attached to the hinder margin of the 
head by means of a small quantity of connecting substance. 
The head of the mature mammalian spermatozoon consists of the 
true head and the head-cap ; the latter often, and very probably always, 
persists. The true head is made up of the anterior and the posterior 
piece which are, in the course of development, derived from the nuclear 
hemispheres detected by Merkel. Between these two portions there is, 
in some Mammals, an internal body in the form of a semilunar and 
sharply- bounded area. 
B. INVERTEBRATA. 
Prof. Haddon’s Collections in Torres Straits. — Some reports have 
now been issued on the zoological collections made by Prof. A. C. 
Haddon in Torres Straits in 1888-9. Mr. E. A. Smith* writes on the 
land Mollusca, of which only a few specimens were collected ; their 
interest lies in the additions made to our knowledge of their geograph- 
ical range, and, in one or two cases, they exhibit considerable variations 
in size. Sixty-six specimens of Lepidoptera, which represent twenty 
species and varieties, are recorded by Mr. G. H. Carpenter ; f Australian, 
Austro-Malayan, and Oriental forms were all found. Mr. R. Kirk- 
patrick J reports on the Polyzoa and Hydrozoa ; of the former twenty- 
seven species were collected, of which four are new, and there are also 
four new varieties ; in the somewhat smaller collection of Hydrozoa 
there were also four new species. 
Mollusca. 
a. Cephalopoda. 
Changes in the Retinal Pigment of Cephalopods.§ — Dr. B. Rawitz 
has experimented with Eledone moschata , Sepia officinalis , and Sepiola 
Bondeletii, and finds that the disposition of the pigment about the retinal 
cells changes when the animals are kept in darkness. It disappears from 
the free, inner ends of the rods, retreating to the posterior basal parts. 
* Scientific Proc. Roy. Dubl. Soc., vii. (1891) pp. 5-13. 
f Tom. cit., pp. 1-5. i Op. cit., vi. (1890) pp. 603-26 (4 pis.). 
§ Zool. Anzeig., xiv. (1891) pp. 157-8. 
1891. 2 T 
