On the Development of the Pycnogons. 191 



ON THE DEVELOPMENT OF THE PYCNOGONS. 



BY GEORGE HODGE. 

 {With a Tinted Plate.) 



In a former part of the Intellectual Observes,* the leading 

 characters of the Pycnogonoidea were briefly glanced at, in 

 such a manner as to serve as an introduction to the study of 

 these animals. 



Observations extending over several years, with admirable 

 opportunities of obtaining a plentiful supply of specimens, 

 have enabled the writer to gather somewhat into form certain 

 vague and conflicting notions regarding them — more particu- 

 larly with reference to their development. 



Few observers have made the development of these ani- 

 mals their study; and in most cases, if not in all, investiga- 

 tion has been directed to the earliest stages of the larvee, owing 

 in a great measure to the extreme difficulty experienced in 

 pursuing the subject further — all attempts to rear the larval 

 forms having failed. 



Developmental studies of the lower forms of life are mostly 

 fitful and uncertain — a fact here, another there, gradually 

 builds up the framework we desire, and enables us to link the 

 whole together. Frequently we may have to wait a year, or 

 even longer, to confirm a single observation, and when this 

 delay is experienced in cases where abundance of material can 

 be obtained, it will readily be conceded, that in the case of rare 

 animals, the progress cannot fail to be slow. This is especi- 

 ally the case with the Pycnogons, for with the exception of the 

 littoral species, few of our marine animals are more difficult to 

 procure. They can only be obtained in a suitable state for 

 developmental studies, by the expenditure of much time, and 

 with considerable personal discomfort. The dredge must be 

 kept going on every possible occasion, to afford a supply of 

 living specimens — and it is the dredger alone who knows the 

 discomfort and uncertainty of this pursuit. 



The generative function in the Pycnogonoidea still con- 

 tinues a profound mystery, with every likelihood of remaining 

 so. It is one of those secrets which defy solution. Not a 

 trace of an internal ovary has been detected ; neither is there 

 any difference in the form of "the male, as compared with the 

 female — so far as has been made out to the present time — 

 further than the well-known " false feet " or " egg-carriers," 

 which in certain genera are only possessed by the so-called 



* July, 1863, Part xviiL 



