274 ILLINOIS BIOLOGICAL MONOGRAPHS [274 



line ducts are always within the longitudinal muscle layer. Monticelli 

 failed to note the position of the vitelline ducts in M. coryphicephala. 



The uterus (Fig. 95) in ripe proglottids is made up of about 18-30 

 slender out-pocketings, which extend well toward the margins of the 

 proglottids but not as far laterad as in certain species of Proteocephalus 

 such as P. fallax, P. dubius, and P. ambloplitis. Monticelli (1891) states 

 that the uterus when filled with eggs causes the ventral surface of the 

 proglottid to belly out. Unfortunately his drawing showing that con- 

 dition has not been reproduced. The uterus (Fig. 94) is ventral and it 

 too lies outside of the internal layer of longitudinal muscles. Uterine 

 pores have not been observed. Monticelli says that they do not exist 

 but that when the uterus is full the ventral body wall ruptures, thus 

 discharging the eggs. A careful study of good material would probably 

 show the presence of one or more uterine pores such as was found by 

 Kramer (1892), Schneider (1905) and by the writer in a large number 

 of Proteocephalids. Monticelli gives no measurements of the uterine 

 eggs. He states that the membranes are quite delicate and that the 

 uterine eggs are very small. In one of Monticelli 's slides a broken pro- 

 glottid rendered some of the eggs visible. The spheroidal embryos 

 measured about 0.015 to 0.017 mm. in diameter. The membranes had 

 become so transparent that they could not be measured. 



In the above description and in the drawings mentioned it has been 

 shown that Monticellia coryphicephala differs from the Proteocephalidae 

 and especially from the typical species of Proteocephalus in a number 

 of characters which concern the position of the genital organs and their 

 relation to the inner longitudinal muscle layer. In all the Proteocepha- 

 lids which have been sufficiently investigated to determine these points 

 the entire genital apparatus with the exception of a portion of the 

 cirrus-pouch and vagina lies within the inner longitudinal muscle layer. 

 Moreover, the follicles of the vitellaria are closely packed about a central 

 duct. In Monticellia the vitellaria are in two broad lateral fields the 

 follicles of which are scattered in a broad single layer. The paired 

 vitelline ducts for a considerable distance lie outside the inner muscle 

 layer. The testes and uterus are entirely outside this muscle layer and 

 the ovary is partly outside of it. As in the Proteocephalidae the vagina, 

 vas deferens and part of the cirrus-pouch are within the inner muscle 

 layer. On account of these marked differences between the Proteo- 

 cephalidae and the form which Monticelli named Tetracotylus coryphi- 

 cephala the writer (1911:474) has seen fit to establish a new genus 

 Monticellia in honor of Professor Monticelli. 



The status of Monticelli 's generic name Tetracotylus has already 

 been reviewed in the introductory section where the new genus has been 



