External sexual Differences in CjiphophtJirilmi. Gihoeellnm 67 



but ill the female they only reacli a proportionately short distance beyond the anterior margin 

 of operculum genitale and at the same time project a litth; into the genital orifice. The 

 latter accordingly exhibits an outline rather conspicuously different in the two sexes, which 

 may be best described by saying that the genital orifice is a hole which is directed straight 

 downwards in the male, but is upun the whole directed somewhat forward in the female. 



In Purcellia there is this remarkable sexual difference, that the fourth tarsus is undivided 

 in the female, but is in the male divided into two joints (PI. IV., fig. 1 m), of which the basal 

 one contains the gland above descril)e(l. There are instances of operculum anale exhibiting 

 a peculiar shape in the male; in PeUalus and especially in Purcellia the entire anal i-egion 

 is extremely different in the two sexes (PI. IV., figs. 1 i and 1 /:). We do not know the 

 female of Pettalus, but we may nevertheless say with certainty, that the character on which 

 Thorell founded this genus, viz. the remarkable appearance of the posterior extremity of the 

 body, is in realit}' only one of the sexual characters of the male in this genus. — We may 

 add that also among Cyphophthalmi the sexual characters of the male appear to have 

 systematic value, being peculiar to each genus, as is the case among Laniatores. 



14. On Gihocellum sudeticuni Steck. 



In 1875 and 1876 Stecker published two papers in German on a most remarkable 

 animal named by him Gibocellum sudeticum and said to have been discovered in the 

 Riesengebirge (Sudeten mountains) in Bohemia, of which papers the first was translated in 

 the Ann. and Mag. of Nat. Hist. The second of these papers, which is entitled " Anatomisches 

 und Histologisches ilber Gihocellum," contains a series of descriptions of the anatomical structure 

 of the animal, particularly the more minute anatomy, illustrated by four plates. These papers 

 have several times been referred to in scientific treatises, but, as far as we are aware, none 

 of the authors who have noticed the histological data have had any hesitation in accepting 

 Stecker's statements, though several of these might well provoke criticism. As an instance 

 of such we may translate^ the following {h, 30-5) : " I have removed the cuticular stratum 

 from the matrix and left the latter in the open air under a watch-glass for about 24 hours^ 

 During this space of time... the chitinogenous membrane of Gibocellum became subject to 

 a very limited process of secretion, the chitinous stratum formed constituting only a very 

 thin covering (of only one-tenth of the thickness of the matrix), consisting of cells which 

 had not yet become distinctly fusiform. The cells are mostly of elliptic shape, though some 

 occur approaching to the fusiform. It is only after 48 hours that the stratum of cells re- 

 covers its former state of development, in which its thickness amounts to about two-thirds 

 of the thickness of the matrix below it; at the same time the stratum acquires a brownish 

 colour, which is vi.sibly due to a secretion from the layer of connective tissue." Surely it 

 is a surprising statement that a "cuticular stratum" consists of cells, though it is less 

 wonderful than that a small animal, 2-5 mm. long, which had been treated in the manner 

 above described, should have been in possession of such vitality that a bit of the chitinogenous 



1 For the reader's convenience we have translated our Dr. Stecker had not been an Austrian-German, the word "die- 

 extracts from the second th) of Stecker's papers; our quota- selbe," on account of its position in this sentence, could only 

 tions from the first (a) are taken from the translation in the refer to " die Cuticularschicht." Therefore we point out that 

 Annals. it cannot possibly have been Stecker's intention to tell what 



- Stecker's own words are : " Ich habe die Cuticularschicht he did with the removed chitine, but he intended to state 



von der Matrix abgetragen, und dieselbe etwa 24 Stunden how the matrix reconstructed the chitinous cuticula. 

 unter einem Uhrglaschen in freier Luft liegen lassen." If 



