annelids, sea spiders, and arachnids, and describing new 

 species of annelids, chaetopods, and gastropodan molluscs. 



There is much authoritative evidence on the accuracy of 

 Krohn's observations and morphological descriptions. These 

 are sufficient to justify the opinion of Kovalevsky, 42 who 

 was shared in the discussion of the nature of the so-called 

 "ventral saddle" of sagitta. Krohn in 184443 considered 

 this formation to be due to the nervous ganglion. Later, 

 W. Busch44 corrected Krohn's opinion, and, in spite of the 

 latter 1 s objection, Busch shared this point of view with 

 Keferstein, R. Leuckart, Pagenstecher, and K. Gegenbaur. 

 Keferstein did not agree with Krohn, but he gave credit to 

 his anatomical investigations: "Krohn, as it is known, 

 related this saddle's very great size to the nervous ganglion. 

 I, together with Busch, do not doubt in that this excellent 

 investigator was in the present question mistaken. "45 



Kovalevsky, again investigating the anatomical structure 

 of sagitta, strongly supported Krohn against the above mentioned 

 authoritative zoologists. "I am against the new investigators," 

 Kovalevsky wrote, "in considering Krohn correct concerning 

 the ventral ganglion, and I hope to convince my readers of 

 this also" (p. 135). "The ventral ganglion," he continued, 

 "has the form of a long oval or quadrangular body with four 

 large nervous trunks, from which two on the anterior end 

 continue to the brain or the cephalic ganglion, connecting, 

 as Krohn showed correctly, with the lateral nerves of the 

 cephalic ganglion" (p. 136) . 



42. A. O. Kovalevsky, "Embryologicheskie issledovaniya chervei 

 i chlenistonogikh" (Embryological investigations of worms 

 and arthropods) (1871), IZBRANNYE RABOTY (Izd. AN SSSR, 

 1951) , pp. 123 - 266. 



43. A. Krohn, ANATOMISCH-PHYSIOLOGISCHE BEOBACHTUNGEN 

 OBER DIE SAGITTA B I PUNCTATA (Hamburg, 1844), 16 pp. 

 This work was published a year later in French (ANN. SC . 

 NAT., 3 Ser., Zool., 3 (1845), pp. 102 - 116) and in 

 English (ANN. NAT. HIST. 16 (1845), pp. 289 - 304). 



44. w. Busch, BEOBACHTUNGEN UBER AN ATOM IE UND 

 ENTWICKELUNG EINIGER WIRBELLOSEN SEETHIERE 

 (Berlin, 1851), viii + 143 pp. 



45. Cited in the article by A. O. Kovalevsky. 



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