350 



THE CRUSTACEA. 



«§>290. 



Htiff and motionless, and may be arranged under the 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 Mysiua, 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 



rmgs, 



(7) 



4 With Cyclopsina castor, the spermatic parti- 

 cles are small, finely-granular, oval corpuscles (see 

 my Beitr. zui- Naturg. d. wirbelloseu Th. p. 41, Taf. 

 II. fig. 4M3 c, or Ann. d. Sc. Nat. XIV. 1840, 

 p. 30, PI. V. B.). As to the other Eutomoslraca, 

 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 (JViegrnann^s Arch. 

 1836, I. p. 369) has observed large, filifurm, fle.KU- 

 ous, spermatic particles with Cypris. I, myself, 

 have found those of Daphnia rcctirostris to con- 

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

 motionless and disappeared by bursting on the ad- 

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

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

 of Glomeris as fusiform cells ; but he was less exact 

 with those of Julus a-nd Polydes7nus, indsscribing 

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



With Julus subuiosus, 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 Miiller^s Arch. 1843, p. 13). 

 Those of the Siphonostoma are, also, of a celloid 

 form ; see Vrey and Leuckart, Beitr. loc. cit. p. 

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



5 Henle (Muller'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 particles of the common 

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

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

 Denkschrift. f. d. gesammt. Naturw. VIII. 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 

 sometmies into 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. 



C Simple capilliform spermatic particles are found 

 with Mysis, Oniscus, Porcellio, Idothea, and 

 Gammarus ; see my researches in Mutter's Arch. 

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

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

 last naturalist (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 fle.xuous incrassation. I have 

 found those of Asellus aquaticus to bo similar, 

 but the cylindrical extremities were straight. 



" The spermatic particles of the Cirripedia, which 

 are simply capillary and very active when fully de- 

 veloped, have been observed by me {Muller''s 

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

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

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

 species of Balanus, and with Chthamalus, Lepas, 

 and Pollicipes. Those oi Litkobius and Geophi- 

 lus present a remarkable aspect from their extreme 

 activity, and may well be recommended for study 

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

 250, Taf. XIU. 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 Ilehninth.* 



* [ § 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 observed, have led to singular views as 

 to their development and character. The recent 

 researches of Kolliker have d(me much to clear up 

 this intricate subject, and these researches have 

 been continued by Wagner and Leuckart (Art. 

 Semen, Cyclop. Anat. ant" Physiol.). The most 

 singular 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 Astacus. 

 Here, the development occurs in special cells Uke that 

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

 er singular 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 

 special cell, but become erect and prominent when 

 the particle escapes. The body of the particle, 

 therefore, is solid, and not hollow and nucleated, 

 as has been supposed (see KiilHker and hia 



