100 MR. NEWPORT ON THE ORGANS OF REPRODUCTION, 



1 . Organs of Reproduction. 



The reproductive parts in lulus are exceedingly interesting on account of their sim- 

 plicity of structure. Treviranus * has described them in the male as two elongated 

 tubes which terminate in separate orifices behind the seventh pair of legs, without any 

 external organ of intromission. In the female, he says, they are composed of a long 

 ovary, formed of two knots of eggs which extend from its outlet in the fourth 

 segment, to its termination beneath the alimentary canal, near the anus; but in 

 this account he has entirely overlooked the essential parts of these organs in both 

 sexes. 



In the male oi lulus terrestris^ the reproductive organs (Plate III. fig. 1.) are two 

 elongated, and sometimes partially convoluted tubes, placed side by side beneath the 

 alimentary canal, immediately above the nervous system, and between the two large 

 salivary vessels. Anteriorly («), they terminate in two organs of intromission, which 

 pass out at the under surface of the seventh segment by distinct orifices, behind the 

 seventh pair of legs. Posteriorly, they extend backwards as far as the middle of the 

 colon. In the anterior third of their course they lie close together {h), but afterwards 

 separate, become smaller, and have developed from their sides, at short distances, 

 a number of minute glandular caeca (c c). Soon after separating they are again 

 connected transversely by three short ducts (d d d), by means of which the two 

 organs communicate freely with each other. Two of these ducts are situated ante- 

 rior, and the third posterior to the first pair of caeca. In the posterior part of the 

 body, each tube is divided into two portions, covered with caeca, and between them 

 there also appear to be some transverse communications, as in the anterior parts of 

 the tubes, but of this I am not fully satisfied. The caeca are of an hour-glass form, 

 and may perhaps be regarded as the proper testes of the animal. They are each 

 connected to the larger, or eflferential tubes, by a short narrow duct (e), the proper 

 efFerential vessel of each caecum or testis. The delicacy and transparency of these 

 parts in an immature individual, allow their structure to be examined with great faci- 

 lity (fig. 2.). They are simple constricted sacs, lined with a thickened mucous 

 membrane (/), and are folds or intussusceptions of the whole muscular, as well as 

 mucous lining of the greater tubes, and from the structure of their interior seem to 

 perform a secretory or glandular function. I have been unable to trace any tubes 

 continued from their larger or caecal terminations, but have seen many minute vessels 

 distributed over their exterior surface (g), that appear to convey a fluid, probably 

 for the purposes of secretion. At first I regarded all these as tracheal vessels, but 

 this cannot indeed be the case, as many of them anastomose with other similar vessels 

 connected with the adipose tissue. On examining the sacs by transmitted light, their 

 interior is distinctly seen to be filled with a fine granulous fluid (h). In those sacs 

 which are nearest the posterior extremity of the organs, the fluid is thin and trans- 

 parent ; but that which is contained in the large tubes, near their anterior termi- 



* Vermischte Schriften Anatomischen und Physiologischen Inhalt. Bremen, 1817. 



