Which genus is identified by eggs with thick shells and radial striations, often with hooklets?

• A. Taenia sp
• B. Hymenolepis nana
• C. Hymenolepis diminuta
• D. Schistosoma japonicum

Answer: (A)

Eggs that have a thick outer shell with radial striations and contain an oncosphere that bears hooklets are classic for Taenia species. The thick, striated shell helps distinguish these eggs from others, and the visible hooklets on the embryo inside are a distinctive feature of Taenia eggs. This combination of shell texture and the armed oncosphere is not typical of Hymenolepis eggs, which tend to be smaller and may show polar filaments rather than pronounced radial striations, nor of Hymenolepis diminuta eggs, which do not display that same radial shell pattern. Schistosoma japonicum eggs have a completely different morphology, including a lateral spine, and lack the thick, striated shell with an armed oncosphere. Therefore, the described eggs point to Taenia.