interest in this sphere of science" Cp. 1). On the coast 

 Grube zealously collected zoological materials and made 

 dissections, considering these studies important for his 

 future embryological investigations. His attention was 

 attracted mainly to annelids, the study of which became 

 his basic zoological specialty. Only in 1839 did Grube turn 

 to work directly on annelid development, beginning with 

 the study of the very small ova of the Saenuris vaviegata 

 described by Hofmeister. In addition he reported that their 

 development differs in many relations from the corresponding 

 phenomena in medical leeches which had been very superficially 

 described by E. Weber. The following spring, Grube studied 

 the embryology of the leech and confirmed the reality of 

 the formerly discovered differences. Preparing the results 

 of his observations for publication, Grube conscientiously 

 studied the works of the authors whom he considered his 

 predecessors. The work of Filippi on the anatomy and 

 embryology of Proboscidae leeches,! 5 recently published, 

 especially interested him. Grube found that in Filippi' s 

 investigations there was only scanty information about the 

 division of the ovum, as the Italian author saw only "six 

 lobes, situated in one and the same plane around the seventh, 

 situated in the center." To this description he added that 

 these spherical segments disintegrate into smaller spheres 

 (GLOBULI ORGANICI), sharing in the formation of the 

 embryo. Filippi apparently studied the developing ova through 

 the membrane of a cocoon, which can explain the indistinct 

 results of his observations. The first foundation of the 

 embryo Filippi described with an indefinite expression-— cutis 

 (LA CUTE) . He also erroneously considered, that the 

 hatched young is nearly similar to the adult leech and at 

 once is attached to the mother by the help of posterior 

 suckers (in fact they are not present at this time) . 



Grube could trace the development of Clepsine in 

 incomparably more detail; his success was aided by the 

 application of concentrated reagents, in particular diluted 

 nitric acid. In the first section of his work, Grube 

 described the structure of the female and male sexual 



15. F. de Filippi, LETTERA AL S. DOTT . RUSCONI SOPRA 

 L'ANATOMIA E LO SVILUPPO DELLE CLEPSINE (Pavia, 

 1839) . 



519 



