850 



THE CRUSTACEA. 



«^290. 



stiff and motionless, and may be arranged under tlie following principal 

 types. 



1. With the Cyclopidae, and Chilognatha, the spermatic particles, which 

 are developed in cells, retain their cell-form to their perfect state, without 

 any trace of processes or appendages/^' 



2. With the Decapoda, they are likewise nearly always of a granular or 

 cell form, but have small, filiform, sac-like processes; sometimes they are 

 divided into two portions by a constriction/'^' 



3. With the Mysina, Amphipoda, and Isopoda, they have the form 

 of very long threads, pointed at both extremities, or with a cylindrical 

 incrassation at one of them. They are motionless, and, upon the addition 

 of water, do not roll up in a loop-like manner. ^'^' 



4. With the Cirripedia, and Chilopoda, they are capillary, very lively, 

 and, from contact with water, become entangled, forming loops and 

 rino-s. ^^^ 



i With Cijclopsina castor, the spermatic parti- 

 cles are small, üiiely-graiiular, oval corpuscles (see 

 my Beitr. zur Naturg. d. wirbellosen Th. p. 41, Taf. 

 II. fig. 41-43 c, or Ann. d. Sc. Nat. XIV. 1840, 

 J). 30, PI. V. B.). As to the other Entomostraca, 

 we have not yet sufficient data to say anything in 

 general. But the form observed with Cyclopsina 

 castor cannot be regarded as a typical one with 

 these animals, for Wagner {fViegman)i''s Arch. 

 1836, I. p. 369) has observed large, filiform, flexu- 

 ous, spermatic particles with Cypris. I, myself, 

 have tound those of Daphnia rectirostris to con- 

 sist of a long, semi-circular body, which became 

 motionless and disappeared by bursting on the ad- 

 dition of water. Stein {Müller''s Arch. 1842, p. 

 263, Taf. XIV. fig. 37, 40) has rightly figured those 

 of Glomeris as fusiform cells ; but he was less e.xact 

 witli those of Julus and Polydenmus, in describing 

 them as small transparent vesicles (Ibid. fig. 36, 39 .) 



With Julus subulosus, they look exactly like 

 very short cylinders containing a very distinct, 

 round nucleus. With Julus hispidus, they are 

 of the same form, but are not nucleated ; while with 

 Julus terrestris, they are conical and nucleated 

 (see my notice in MüUer''s Arch. 1843, p. 13). 

 Those of the Siphonostoma are, also, of a»celloid 

 form ; see t'rey and Leuckart, Beitr. loc. cit. p. 

 135, Taf. II. fig. 21 (Caligus). 



5 Henle (3Juller\s Arch. 1835, p. 603, Taf. XIV. 

 fig. 12) and myself (Ibid. 1836, p. 26, Taf. III. 

 fig. 23, 24) first called attention to the singular 

 form of the spermatic iiarticles of the common 

 craw fish ; but, subsequently, Kölliker (Beitr. &c. 

 1841, p. 7, Taf. II. III. and in the Schweizerisch. 

 Denkschrift, f. d. gesammt. Naturw. Vlll. 1846, 

 p. 26, Taf. II.) has shown that those of the most di- 

 verse species of Brachyura, Anomura, and Macru- 



ra, are motionless, radiated cells, one part of 

 which is separated by a constriction, and prolonged 

 sometunes mto a kind of peduncle ; the rays 

 are often only three or four in number, and the 

 cells themselves are sometimes conical or cylindri- 

 cal. The most simple of these spermatic particles 

 are observed with Crangon vulgaris, and Palae- 

 mon squilla ; and, according to my own observa- 

 tions, consist only of flattened cells with a short 

 pointed process. 



•' Simple capilliform spermatic particles are found 

 witli Mysis, Oniscus, Porcellio, Idothea, and 

 Gamniarus ; see my researches in Miiller^s Arch. 

 1836, p. 27, Taf. III. hg. 19, 20, and Ibid. 1837, 

 p. 433 ; also Kölliker, Beitr. loc. cit. p. 15. This 

 last natui-aUst (Beitr. &c. p. 14, Taf. III. fig. 28, 

 29) has stated that the long capillary, but motion- 

 less spermatic particles of Iphimedia obesa and 

 Hyperia medusarum are terminated by a cylin- 

 drical and slightly fiexuous incrassation. I have 

 found those of Asellus aquaticus to be similar, 

 but the cylindrical extremities were straight. 



7 The spermatic particles of the Cirripedia, which 

 are simply capillary and very active when fully de- 

 velojjed, have been observed by me (Midler's 

 Arch. 1836, p. 29), with Balanus pusillus, and 

 by Kölliker (Beitr. p. 16, Taf. III. fig. 30, and 

 Schweiz. Denks. loc. cit. p. 33) with many other 

 species of Balanus, and with Chtliamalus, Lepas, 

 and Pollicipes. Those of Lit ho Iji us and Geophi- 

 lus present a remarkable aspect from their extreme 

 activity, and may well be recommended for study 

 from their size {Stein, in Muller's Arch. 1842, p. 

 250, Taf. XIII. XIV. fig. 19-33). Treviranus 

 (Verm. Schrift. II. p. 26, Taf. VI. fig. 2, 3) has 

 taken those of Scolopendra, which are bound to- 

 gether in a long white cord, for a Hehninth.* 



* [ § 290, note 7.] The spermatic particles of 

 the Crustacea are the most remarkable of any in 

 the whole animal kingdom. The strange, bizarre 

 forms, here oliserved, have led to singular views as 

 to their development and character. The recent 

 researches of Kölliker have done much to clear up 

 this intricate subject, and these researches have 

 been contuiued by fVagner and Leuckart (Art. 

 Semen, Cyclop. Anat. and Pliysiol.). The most 

 Bingular of these particles, as is well known, are those 

 belonging to the higher forms of this class. The de- 

 velopment and nature of these I have recently stud- 



ied, and with results quite different from those of the 

 authors just mentioned. My observations were made 

 on those of Pagurus, Pilumnus and Jstacus. 

 Here, the devclojimenl occurs in special cells like that 

 of those of other animals, and the particle, howev- 

 er smgular its form, is the transformed nucleus of 

 these cells. The spine-like processes lie reverted 

 on the body of the particle when this last is in the 

 si)ecial cell, but become erect and jjrominent when 

 the particle escapes. The body of the particle, 

 therefore, is solid, and not hollow and nucleated, 

 as has been supposed (see Kölli'cer and bia 



