No. 4-] THE EYE OF SCUTIGERA FORCEPS. 213 



ommatidium, touching with their proximal ends the basal mem- 

 brane. In the inner tier there are from three to four cells 



The cells of (5) and (6) secrete, upon their inner surfaces, 

 rhabdoms, and from the outer side send out a process consti- 

 tuting the nerve fibers. 



These nerve fibers were mentioned by Adensamer, but his 

 figures failed to show the direct connection between the fibers 

 and the cells of the middle and inner tiers. 



In macerated preparations I have been able to show this 

 beyond doubt (Fig. i C, D), and in the ommatidium, before 

 it has been separated into its component parts, have observed 

 the passage of these fibers through the basal membrane. 



The expanded proximal portions of the elongated pigment 

 cells (Fig. i B, /) form the layer of pigment spoken of by 

 Adensamer, as found on the basal membrane. 



(7) Supplementary cells, four in number, are found at the 

 same level as the cells of the inner tier. They are entirely 

 different, and thus easily distinguished from the cells of the 

 inner tier (a, Fig. i D). 



(8) As shown in Fig. 2 A certain large nuclei were found 

 in cross-sections at the distal part of the ommatidium. They 

 are found only in the space between three ommatidia. They 

 were not observed, nor the cells to which they belong, in 

 maceration preparations. 



BRYN MAWR COLLEGE, April, 1900. 



REFERENCES. 



'80 GRENACHER. Ueber die Augen einiger Myriapoden. Arch.f. jnikr. 



Anat. 1880. 

 '93 ADENSAMER. Zur Kenntnis der Anatomic und Histologie von Scu- 



tigera coleoptrata. Verh. d. Bot. Ges. Wien. Bd. xliii. 

 '96 ROSENSTADT. Zur morphologischen Beurtheilung der Augen von 



Scutigera. Zool. Anzeiger. Jahrg. xix. 1896. 



