In a letter to Johannes Miiller sent on February 2, 1853 

 from Messina, 59 he reported: "I have at the same time studied 

 the development of sagitta. What Darwin has said about it 

 relates to the development of any fish" (p. 141) (136). 

 Krohn did not publish any further special work on the 

 development of sagitta. 



Of Krohn' s two articles on Cirripedia, one concerns 

 the structure of the cement gland of Lepas anatifera and 

 Conohoderma virgata and the anatomy of the female genital 

 system of Lepas and Balanus trintennabulwn . The other^O 

 includes some data about larval development. Krohn described 

 the intermediate stage between the young larva which is 

 similar to the nauplius of the copepods and the late cirripes- 

 shaped larva. The work is illustrated with graphs of very 

 young larva of cirripeds, and also larvae of Balanus species 

 and Lepas antifera. 



The development of gastropodan molluscs (pteropods and 

 heteropods) was the subject of four reports, the last with 

 the character of a detailed monograph. ^1 in these investiga- 

 tions his main attention is given to a detailed description 

 of larvae of pteropods (subclass opisthobranchia) : Cymbulia 

 Peronii, Tiedemannia neapolitana, Gastropteron Meokelii 3 and 

 also the larvae of carinate molluscs (subclass prosobranchia) 

 Pterotraohea (two species) , Carinaria mediterranean and 

 Fir-iolides (Figure 44) . 



59. ARCH. ANAT., PHYSIOL. (1853), p. 137. 



60. A. Krohn, "Beobachtungen iiber die Entwickelung der 

 Cirripedien," ARCH. NATURG . , 26, 1 (1860), pp. 1 - 8. 



61. A. Krohn, "Beobachtungen aus der Entwickelungsgeschichte 

 der Pteropoden, Heteropoden, und Echinodermen. Brief 1. 

 Mitt. a. d. Herausgeb.," ARCH. ANAT., PHYSIOL. 

 (1856), pp. 515 - 522; "Beitrage zur Entwickelungs- 

 geschichte der Pteropoden und Heteropoden," ibid . (1857), 

 pp. 459 - 468; "Uber die Schale und die Larven des 

 Gastropteron MeckelM," ARCH. NATURG., 26, 1 (1860), 

 pp. 64 - 68; BEITRAGE ZUR ENTWICKELUNGSGESCHICHTE 

 DER PTEROPODEN UND HETEROPODEN (Lepizig, 1860), 



46 pp. 



573 



