INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 



603 



cient to fill more than a page, even when stated in a tabular form, arc 

 to be found in the female organs. Dr. Brock sums up his results in 

 the following fashion : — 



(1) All typical ffigopsida possess two symmetrical oviducts. 



(2) The same is true of all typical Octoijoda. 



(8) The forms in which one oviduct is wanting (Myopsida) arc in 

 all points the most ditterentiatcd ; so that it follows that the double 

 oviduct is the oldest form of the female generative apparatus, and 

 that all forms with one only have lost the other by reduction of the 

 l)arts. 



The following tables will exhibit the leading diiicrcnccs between 

 some of the most important genera : — 



Nidamcntal glands 



Oviducts .. 



Kitdiila 



Anal appondagcs 



Infnndibular valve 



"8i)lcou" .. 



Omniastrcplios. 



+ 

 2 

 Complicated 

 Asymmetrical 

 + 

 



Euoploteutliis. 







2 



Simi)lc 



Symmetrical 



+ 



+ 



Owciiia. 



II. 



Shell 



ACCCSS017 hearts .. 

 Nidamcntal glands 

 Arms 



Oiuinastrcphcs 

 sagittatus. 



Onycbotcuthis. 



Witli phragmocoue With phragmocono 



Absent 



+ 



With suckers 



Enoploteutbis. 



(Without phragmo- 

 t, cone, 



brnnches of the 



(Developed on the 



\ cephulic and posterior aorta). 



+ I 



/With hooks and\ ,,,.., , , , 

 1 «npl.-,.v. h ^Viih hooks onl 



suckers 



One of tlic next important questions is the meaning of the shell of 

 Sepia ; in other points — musculature, radula, loss of superior salivary 

 glands, forna of liver and of ink-bag, absence of connnissure between 

 the ganglia stellata and in the fusitm of the accessory nidamental 

 glands — this form appears to be one of the most dilierentiated of tho 

 Decapoda. Why, then, docs it retain its shell? In other words, 

 Has Sepia been derived from Loligid forms, and had the simple 

 horny shell furtlier developed ? — or (2) Did Sepia separate very 

 early from the Dibrancliiatc stem, and get its various other characters 

 ind(!i)endently of the other forms? — or (3) Is Sepia the direct de- 

 scendant of the Belemnitcs, and have the oDshoots each independently 

 lost their calcareous shell V The first h3'pothesis is opposed by 

 jialicoiitidogy ; no evidence supports the second. Tho third view is 

 the m<ist satisfactory, inasniucli as it seems Ihc; Decapoda exhibit a 

 marked tendency to lose their shell, while Spirula, with its still 



